Micro-Centrifuge Tubes have molded external graduation marks at 100µl increments that are clear and easy to read, similar in style to marks used on graduated glassware. Tubes have a flat frosted top and a frosted marking area on the side of tube for writing. Hinged lid provides a soft piercing point for inserting a needle. Made from a clear copolymer designed for high speed centrifugation and boiling.